title: Cloning, characterization and analysis of expression profiles of a cDNA encoding a hyoscyamine 6beta-hydroxylase (H6H) from Atropa baetica Willk.
abstract: A new cDNA encoding hyoscyamine 6beta-hydroxylase (H6H, EC 1.14.11.11), a bifunctional enzyme catalyzing the last two steps in the biosynthesis of scopolamine, was isolated from Atropa baetica roots (GenBank accession no. EF442802). The full cDNA sequence showed an ORF of 1035bp, coding for a protein with 344 amino acid residues. Sequence analyses at the nucleotide level showed that this ORF shares high identity with other H6H from different plant species, such as Anisodus tanguticus and Hyoscyamus niger with 90% identity, and an almost total identity with A. belladonna (98%). Tissue expression analyses showed that the gene transcript was tissue dependent, appearing exclusively in roots, thus being the only biosynthetic site for the production of scopolamine. Furthermore, Southern hybridization experiments revealed that this gene was not part of a multigene family as appears in low copy number. Phylogenetic tree analysis indicated that A. baetica H6H had a very close relationship with A. belladonna and to a lesser extent with H. niger.
authors.affiliation: Instituto Universitario de Bio-Orgánica AG González, University of La Laguna, 38206 La Laguna, Tenerife, Spain.
authors.forename: Nabil
authors.initials: N
authors.lastname: El Jaber-Vazdekis
authors.forename: Celedonio
authors.initials: C
authors.lastname: González
authors.forename: Angel G
authors.initials: AG
authors.lastname: Ravelo
authors.forename: Rafael
authors.initials: R
authors.lastname: Zárate
mesh_terms: D032282:Atropa / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D018076:DNA, Complementary; D020869:Gene Expression Profiling; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D012601:Scopolamine / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D012601:Scopolamine; D006899:Mixed Function Oxygenases; C052273:hyoscyamine (6S)-dioxygenase